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目的了解不同食品中产志贺毒素大肠杆菌的流行情况、菌株特征及潜在致病性。方法对我国不同地区采集的355份食品样品进行产志贺毒素大肠杆菌分离鉴定,对菌株进行stx1/stx2基因分型、eae等毒力基因检测,并对菌株进行多位点序列分型(MLST)分析。结果 355份样品中44份stx2基因阳性,共分离出11株非O157产志贺毒素大肠杆菌,其中3株携带stx2a亚型,3株携带stx2e亚型,1株携带stx2b亚型,4株不能分型;5株携带ehxA、saa毒力基因,2株携带subA基因,1株携带katP基因;MLST将11株菌分为7个不同的ST型,存在与溶血性尿毒综合症患者肠出血性大肠杆菌分离株(HUS-associated enterohemorrhagic E.coli,HUSEC)及主要流行血清群产志贺毒素大肠杆菌亲缘关系较近的ST型别。结论我国食品中存在一定程度的非O157产志贺毒素大肠杆菌污染,部分菌株具有潜在致病性,应加强对食品中STEC的监测。
Objective To understand the epidemiology, strain characteristics and potential pathogenicity of Shiga toxin-producing Escherichia coli in different foods. Methods Isolation and identification of Shiga Toxigenic Escherichia coli isolated from 355 food samples from different regions of China were carried out. Stx1 / stx2 genotyping, eae and other virulence genes were detected in the strains. The strains were classified by MLST )analysis. RESULTS: Forty-four strains of stx2 gene were positive in 355 samples. A total of 11 strains of non-O157 Shiga toxin-producing Escherichia coli were isolated, of which 3 were stx2a, 3 were stx2e, 1 were stx2b and 4 were not 5 strains harboring ehxA and saa virulence genes, 2 strains carrying subA gene and 1 strain carrying katP gene. MLST divided 11 strains into 7 different ST types, HUS-associated enterohemorrhagic E. coli (HUSEC) and ST-serotypes of the major epidemic serogroup Shiga toxin-producing Escherichia coli. Conclusion There is a certain degree of non-O157 Shiga toxin-producing Escherichia coli in our food which is contaminated. Some strains are potentially pathogenic. Therefore, the monitoring of STEC in food should be strengthened.